aquarium matten filter

Print it with PETG, because PLA dissolves more easily in water.

GREAT FOR SHRIMP / CORY

There are a lot of people in Germany who threw their Eheim Filters away and went for the internal Mattenfilter solution. Following the forums over here I did not find one post that was not totally happy with that system concerning its ability to filter biologically with no need to service and maintenance.
It is cheap as it is only a pump and a foam mat.
The downside on this filter is, that it is in your tank and takes quite some space. Some people hide it with moss.